Analysis of spatio-temporal variation of crop yield in China using stepwise multiple linear regression

2021 ◽  
Vol 264 ◽  
pp. 108098
Author(s):  
Yingxia Liu ◽  
Gerard B.M. Heuvelink ◽  
Zhanguo Bai ◽  
Ping He ◽  
Xinpeng Xu ◽  
...  
PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243589
Author(s):  
Hiroshi Akima ◽  
Akito Yoshiko ◽  
Régis Radaelli ◽  
Madoka Ogawa ◽  
Kaori Shimizu ◽  
...  

Muscle quality is well-known to decrease with aging and is a risk factor for metabolic abnormalities. However, there is a lack of information on race-associated differences in muscle quality and other neuromuscular features related to functional performance. This study aimed to compare muscle quality, function, and morphological characteristics in Japanese and Brazilian older individuals. Eighty-four participants aged 65–87 years were enrolled in the study (42 Japanese: 23 men, 19 women, mean age 70.4 years; 42 Brazilians: 23 men, 19 women, mean age 70.8 years). Echo intensity (EI) and muscle thickness (MT) of the quadriceps femoris were measured using B-mode ultrasonography. A stepwise multiple linear regression analysis with EI as a dependent variable revealed that MT was a significant variable for Japanese participants (R2 = 0.424, P = 0.001), while MT and subcutaneous adipose tissue (SCAT) thickness were significant variables for Brazilian participants (R2 = 0.490, P = 0.001). A second stepwise multiple linear regression analysis was performed after excluding MT and SCAT thickness from the independent variables. Sex and age for Japanese participants (R2 = 0.381, P = 0.001) and lean body mass and body mass index for Brazilian participants (R2 = 0.385, P = 0.001) were identified as significant independent variables. The present results suggest that MT is closely correlated with muscle quality in Japanese and Brazilian older individuals. Increases in muscle size may induce decreases in intramuscular adipose tissue and/or connective tissues, which are beneficial for reducing the risks of metabolic impairments in Japanese and Brazilian older individuals.


2019 ◽  
Vol 35 (1) ◽  
pp. 9-14 ◽  
Author(s):  
P. S. Maya Gopal ◽  
R Bhargavi

Abstract. In agriculture, crop yield prediction is critical. Crop yield depends on various features which can be categorized as geographical, climatic, and biological. Geographical features consist of cultivable land in hectares, canal length to cover the cultivable land, number of tanks and tube wells available for irrigation. Climatic features consist of rainfall, temperature, and radiation. Biological features consist of seeds, minerals, and nutrients. In total, 15 features were considered for this study to understand features impact on paddy crop yield for all seasons of each year. For selecting vital features, five filter and wrapper approaches were applied. For predicting accuracy of features selection algorithm, Multiple Linear Regression (MLR) model was used. The RMSE, MAE, R, and RRMSE metrics were used to evaluate the performance of feature selection algorithms. Data used for the analysis was drawn from secondary sources of state Agriculture Department, Government of Tamil Nadu, India, for over 30 years. Seventy-five percent of data was used for training and 25% was used for testing. Low computational time was also considered for the selection of best feature subset. Outcome of all feature selection algorithms have given similar results in the RMSE, RRMSE, R, and MAE values. The adjusted R2 value was used to find the optimum feature subset despite all the deviations. The evaluation of the dataset used in this work shows that total area of cultivation, number of tanks and open wells used for irrigation, length of canals used for irrigation, and average maximum temperature during the season of the crop are the best features for better crop yield prediction on the study area. The MLR gives 85% of model accuracy for the selected features with low computational time. Keywords: Feature selection algorithm, Model validation, Multiple linear regression, Performance metrics.


2021 ◽  
Author(s):  
Xiaotong Han ◽  
Minjie Zou ◽  
Zhenzhen Liu ◽  
Yi Sun ◽  
Charlotte Aimee Young ◽  
...  

Abstract Background: Cataract is the leading cause of blindness globally and more people will be at risk for this common cause of vision loss in the coming years.To estimate the disease burden of cataract and evaluate contributions of various risk factors to cataract-associated disability-adjusted life years (DALYs).Methods: Prevalence of visual impairment due to cataract and disability-adjusted life years of cataract were extracted from the Global Burden of Disease (GBD) study 2019 to explore time trends and annual changes. Regional and country-level socioeconomic indexes were acquired from open databases, and stepwise multiple linear regression was used to evaluate associations between age-standardized rate of DALYs of cataract and potential predictors.Results: Global Prevalence rate of visual impairment due to cataract rose by 58.45% from 791.4 per 100,000 population (95%CI: 705.2 to 890.0 per 100,000 population) to 1253.9 per 100,000 population 95%CI: 1103.3 to 1417.7 per 100,000 population) in 2019 and DALYs rate of cataract rose by 32.18% from 65.3 per 100,000 population (95%CI: 46.4 to 88.2 per 100,000 population) in 1990 to 86.3 per 100,000 population (95%CI: 61.5 to 116.4 per 100,000 population) in 2019.Stepwise multiple linear regression model showed that higher refractive error prevalence (β=0.036, 95% CI: 0.022, 0.050, P<0.001), lower number of physicians per 10,000 population (β=-0.959, 95% CI: -1.685, -0.233, P=0.010) and lower level of HDI (β=-134.93, 95% CI: -209.84, -60.02, P=0.001) were associated with higher disease burden of cataract.Conclusions: Substantial increases in the prevalence of visual impairment and DALYs of cataract were observed from 1990 to 2019. Successful global initiatives targeting improving cataract surgical rate and quality, especially in regions with lower socioeconomic status, is a prerequisite to combating this growing burden of cataract in the aging society.


2014 ◽  
Vol 46 (5) ◽  
pp. 671-688 ◽  
Author(s):  
J. Ding ◽  
U. Haberlandt ◽  
J. Dietrich

Three different methods are compared to estimate the instantaneous peak flow (IPF) from the corresponding maximum daily flow (MDF), as the daily data are more often available at gauges of interest and often with longer recording periods. In the first approach, simple linear regression is applied to calculate IPF from MDF values using probability weighted moments and quantile values. In the second method, the use of stepwise multiple linear regression analysis allows to identify the most important catchment descriptors of the study basin. The resulting equation can be applied to transfer MDF into IPF. With the third method, the temporal scaling properties of annual maximum flow series are investigated based on the hypothesis of piece wise simple scaling combined with the generalized extreme value distribution. The scaling formulas developed from three 15 min stations in the Aller-Leine river basin of Germany are transferred to all daily stations to estimate the IPF. The method based on stepwise multiple linear regression gives the best results compared with the other two methods. The simple regression method is the easiest to apply given sufficient peak flow data, while the scaling method is the most efficient method with regard to data use.


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